In many hydraulic applications, it is necessary to connect two sections of pipe together using a coupling which will also permit disconnection at a later period in time. Many times it is necessary to connect two lengths of pipe together using an intervening pipe so as to take up longitudinal play between two fixed pipes. Such is true especially in hydraulic lines used on agricultural and earth moving equipment wherein it is difficult to maintain precise alignment in spacing of parts. In addition, a satisfactory installation of hydraulic lines on motor vehicles normally entails the use of coupling fittings.
One type of a pipe fitting is taught in U.S. Pat. No. 4,309,050. In this particular patent, a serrated collar is used which mates with serrations formed on the inserted end of the pipe. Such a fit is beneficial for high pressure fluid connections but the fit has a disadvantage in that after repeated connections and disconnections, the serrated fit fails to tightly couple the pipes together. In addition, the use of two such couplings on the ends of an intervening length of pipe prevent longitudinal shifting of the pipe relative to the two unions.
Now a pipe coupling has been invented which is capable of being coupled and uncoupled repeatedly while at the same time permitting longitudinal shifting of an intervening length of pipe.